Plasma display panels (PDP) can be divided into two types, the direct current (DC) type and the alternating current (AC) type, according to their electrical driving mode. A conventional AC-type PDP, glass plates undergo several manufacturing steps in which many functional layers are formed thereon and are then combined together by sealing the periphery of the glass plates. A mixed gas with a predetermined ratio is then introduced into the discharge units between the glass plates.
In FIG. 1, a plurality of parallel electrodes 12 and 14 are alternatively arranged on the front plate 10. The two electrodes are respectively used as the scan electrode and the common electrode. The electrode 12 is composed of a bus electrode 12a and a transparent electrode 12b. The electrode 14 is composed of a bus electrode 14a and a transparent electrode 14b. A dielectric layer 16 and a protective layer 18 are sequentially formed on the electrodes 12 and 14. Similarly, a plurality of parallel address electrodes 20 is formed on the back plate 12. A dielectric layer 22 is formed on the address electrode 20. A plurality of parallel barrier ribs 24 are formed on the dielectric layer 22. Each barrier rib 24 is located between adjacent address electrodes 20. A fluorescencer 64 is coated on the barrier ribs 24. Electrodes 12 and 14 on the front plate 10 and address electrode 20 on the back plate 12 are perpendicularly crossed. The barrier ribs 24, electrode 12 and electrode 14 comprise a discharge unit 28 as illustrated in the FIG. 2.
FIG. 2 is a schematic, cross-sectional view of a discharge unit. In a conventional AC-type PDP 10, referring to FIGS. 1 and 2 simultaneously, a plurality of parallel-arranged transparent electrodes 12b are formed on the front plate 10. When a voltage is applied to a specific discharge unit 28 to induce discharge, the mixed gas in the discharge unit 28 emits ultraviolet (UV) rays to light the fluorescencer 26 inside the discharge unit 28. The fluorescencer 26 then emits a visible light, such as a red (R), green (G) or blue (B) light. According to this structure, the fluorescencer 26 can only be coated on the sidewalls of the barrier ribs and the top surface of the dielectric layer 22, so that only three planes are utilized.
Since an erroneous discharge may occur in a non-discharge region B, illustrated in FIG. 3, of the conventional AC-type PDP, the distance d between two discharge units 30 of two adjacent discharge regions A must be increased to prevent the same. Although a larger non-discharge region B prevents erroneous discharge, discharge regions A are then relatively contracted, i.e. have a reduced opening ratio, and luminescence efficiency is thus decreased. Conversely, a smaller non-discharge region B provides larger discharge regions A, but erroneous discharge then readily occurs, so that neighboring discharge regions A are affected during operation.
A conventional method for solving the erroneous discharge issue in non-discharge region B is to develop different barrier rib structure as illustrated in the FIG. 4. For example, a Waffle structure 24 having sealed latticed barrier ribs has been provided. This structure uses barrier rib to isolate the discharge region A and the non-discharge region B. The discharge region A is a closed space according to this structure. Therefore, the problem of erroneous discharge occurring in the non-discharge region B is solved. On the other hand, the fluorescencer can be coated on the five planes of each discharge unit, i.e. front, back, left, right and bottom planes, thereby improving luminescence efficiency by increasing the fluorescencer coating area.
However, in the conventional method, the vacuuming and gas refilling steps are performed between the discharge region A and non-discharge region B after the front and back glass plates of the PDP are adhered to each other, so the closed discharge and non-discharge regions results in greater difficulties during performance of the two steps. To avoid the above problem, the front plate requires a new design to form a height difference in the surface of the front plate, so that some gas channels are formed after the front and back glass plates of the PDP are adhered to each other. The vacuuming and refilling gas steps is improved through these gas channels. However, the structure requires redesign of the front plate, which increases manufacturing difficulties. According to the above descriptions, the barrier rib structure of a conventional PDP has many drawbacks; for example, the structure is prone to erroneous discharge, the luminescence efficiency is low, or the structure is hard to vacuum.